1. Field of the Invention
This invention relates to computer architecture and, more particularly, to an architecture and apparatus for effectively associating a plurality of different sources of information with a plurality of different destinations for such information in a computer system.
2. History of the Prior Art
Computer designers are working toward providing systems which will allow an operator sitting at a personal computer to call up information from a number of different sources. For example, it is expected that a person will be able to hear telephone and radio communications, view television or recorded motion pictures, play stereo recordings of music, and operate computer graphical and text programs. It is also expected that all of these operations will be possible at the same time so that, for example, a television program may be displayed in one window of an output display while a computer graphics program is running in another window of the same display or computer graphics material is displayed as an overlay on the television program.
Not only are these designers interested in taking information from a plurality of different sources, they are also interested in utilizing such information at a number of different destinations all of which may operate in different formats. For example, information might be presented on a computer output display, sent to a television set, transferred to a stereophonic sound system, sent to a local area network, or furnished to a myriad of other devices.
Many, if not all, of the sources of information which one would like to utilize present information in entirely different formats. For example, video information may be offered in the format used for television transmission while computer processors and sound systems provide information in other formats. If television (video) signals are to be displayed with computer graphics signals on the same output monitor, the analog television signals should first be converted to digital representations for presentation on a computer monitor. Moreover, the television signals are presented at a different frequency in an interlaced pattern consisting of two time-separated fields while a typical computer display presents more lines of data in a non-interlaced mode. Although both types of signals are electrical, they arrive in entirely different formats for their two purposes.
To complicate the problem, the various destinations to which information is directed from these diverse format sources may in a similar manner operate in formats which are different from each other and from the formats of the sources. For example, to present television and graphics signals on the same output display requires that the format of one or the other be changed to the format which the output display utilizes.
The transferring of information from one format to another has usually been done on an ad hoc basis so that it must be repeated for each source of information and each destination for information to be used with each computer system. This is not an economic or logical process for developing computer systems.